Intraosseous myofibroma mimicking an odontogenic lesion: case report, literature review, and differential diagnosis.

BACKGROUND: Intraosseous myofibroma of the jaw is a rare neoplasm of mesenchymal origin with limited comprehensive understanding. It typically affects patients in the first two decades of life with a male predilection. CASE PRESENTATION: This study presents a rare case of myofibroma mimicking an odontogenic lesion in a 2-year-old boy. The patient presented with an incidental finding of a painless swelling of the right mandibular ramus of unknown etiology. Imaging analysis revealed a solid, expansile lesion adjacent to the germinal zone of the right mandibular first molar. Histopathologic analysis and immunohistochemistry after incisional biopsy suggested a possible central odontogenic fibroma, and the patient underwent total enucleation, leading to the final diagnosis of intraosseous myofibroma. Follow-up examinations showed no evidence of recurrence. CONCLUSIONS: This report contributes to the understanding of myofibroma in pediatric patients and underscores the critical role of meticulous histopathologic examination for effective surgical planning and optimal patient outcomes.

Double-Flap Elevation From the Ipsilateral Lower Extremity: The Anterior Approach to Fibula Osteo-Cutaneous Flap Elevation.

ABSTRACT: The free fibular flap has been elevated by a "lateral approach" from the posterior edge of the peroneal muscle for more than 40 years. However, in this approach, the surgical view is limited because flap elevation in mandibular reconstruction is performed simultaneously with tumor resection in the supine position, even when using positioning pillows. We herein propose an "anterior approach" as a new surgical method. We retrospectively investigated free fibular flap surgeries performed using the anterior approach, which consists of three anterior approaches, over a seven-year period. First, to avoid the course of the superficial peroneal nerve, the crural fascia was incised 1-2 cm posterior to the anterior edge of the peroneal muscle. The anterior edge of the peroneus muscle is detached from the anterior intermuscular septum. After performing osteotomies distal and proximal to the fibula, the interosseous membrane was incised from the anterior view. Pulling out the fibula to the anterior space between the anterior intermuscular septum and the peroneal muscle made the surgical field shallow. No postoperative superficial or deep peroneal nerve palsies were found in the 55 patients. Only one tourniquet was used in 31 of the 55 cases (56.4%), with an average of 95 min. Twenty-four patients (43.6%) required a second tourniquet 38 min after an interval. Only one tourniquet was used in 25 of the 30 (83.3%) cases in the last 3 years. Moreover, double flaps were used in 21 cases (38.2%), all of which involved ipsilateral ALT flaps. In 18 cases, double-flap elevation and prefabrication were successfully finished before the completion of tumor resection by otorhinolaryngologists.

[The use of «growing¼ endoprostheses in the complex treatment of children with post-resection mandibular defects]. / Primenenie «rastushchikh¼ endoprotezov v kompleksnom lechenii detei s postrezektsionnymi defektami nizhnei chelyusti.

THE AIM OF THE STUDY: To develop and implement a comprehensive algorithm for the rehabilitation of patients after partial resection of the mandible using a titanium «growing¼ endoprosthesis. MATERIAL AND METHODS: The study included 16 patients aged 2 to 7 years, with benign (6 cases) and malignant (10 cases) tumors of the mandible. The patients were divided into 2 groups depending on the time of fixation of the endoprosthesis. Group 1 included patients with simultaneous installation of a prosthesis (7 people). Group 2 included patients with delayed installation of an endoprosthesis (9 people). For the reconstruction of the mandible, «growing¼ titanium endoprostheses made of Ti6Al4V alloy of various designs were used. Removable orthodontic devices of mechanical and functional type of action, standard elastic mouthguards were used in the process of dental treatment. RESULTS: A comprehensive algorithm has been developed for the rehabilitation of children after partial resection of the mandible, depending on the time of fixation of the prosthesis and the volume of surgical intervention. CONCLUSION: The developed algorithm of complex rehabilitation using a «growing¼ endoprosthesis and dental support at the pre and postoperative stages allows to reduce the volume of secondary deformation of facial structures and dentition.

Accuracy of the surgical execution of virtually planned deep circumflex iliac artery flaps and their appropriateness for masticatory rehabilitation.

BACKGROUND: Tumorous diseases of the jaw demand effective treatments, often involving continuity resection of the jaw. Reconstruction via microvascular bone flaps, like deep circumflex iliac artery flaps (DCIA), is standard. Computer aided planning (CAD) enhances accuracy in reconstruction using patient-specific CT images to create three-dimensional (3D) models. Data on the accuracy of CAD-planned DCIA flaps is scarce. Moreover, the data on accuracy should be combined with data on the exact positioning of the implants for well-fitting dental prosthetics. This study focuses on CAD-planned DCIA flaps accuracy and proper positioning for prosthetic rehabilitation. METHODS: Patients post-mandible resection with CAD-planned DCIA flap reconstruction were evaluated. Postoperative radiograph-derived 3D models were aligned with 3D models from the CAD plans for osteotomy position, angle, and flap volume comparison. To evaluate the DCIA flap's suitability for prosthetic dental rehabilitation, a plane was created in the support zone and crestal in the middle of the DCIA flap. The lower jaw was rotated to close the mouth and the distance between the two planes was measured. RESULTS: 20 patients (12 males, 8 females) were included. Mean defect size was 73.28 ± 4.87 mm; 11 L defects, 9 LC defects. Planned vs. actual DCIA transplant volume difference was 3.814 ± 3.856 cm³ (p = 0.2223). The deviation from the planned angle was significantly larger at the dorsal osteotomy than at the ventral (p = 0.035). Linear differences between the planned DCIA transplant and the actual DCIA transplant were 1.294 ± 1.197 mm for the ventral osteotomy and 2.680 ± 3.449 mm for the dorsal (p = 0.1078). The difference between the dental axis and the middle of the DCIA transplant ranged from 0.2 mm to 14.8 mm. The mean lateral difference was 2.695 ± 3.667 mm in the region of the first premolar. CONCLUSION: The CAD-planned DCIA flap is a solution for reconstructing the mandible. CAD planning results in an accurate reconstruction enabling dental implant placement and dental prosthetics.

Large Complex Odontoma in the Angulus Mandibulae - Intraoral Enucleation as an Alternative to Mandibular Continuity Resection.

BACKGROUND: Odontomas are among the most common odontogenic tumors and are generally considered as hamartomatous odontogenic lesions. These tumors can be histopathologically divided into complex odontomas and compound odontomas based on their composition. Odontomas show a slow growing behavior and typically lack characteristic symptoms. The standard surgical treatment for large odontogenic tumors is a mandibular (continuity) resection followed by primary or secondary plastic reconstruction. CASE REPORT: A 22-year-old male presented to the Department of maxillofacial surgery with an increasing feeling of pressure in the left mandible. An orthopantomogram revealed a large complex odontoma rg 038. Instead of mandible continuity resection an alternative minimally invasive technique/approach (intraoral) with a trapezoidal bone flap for the enucleation of an odontoma of the mandibular angle with subsequent flap reimplantation and osteosynthesis was performed. CONCLUSION: Surgical enucleation of large mandibular odontoma with a continuity resection through an extraoral approach represents the surgical standard treatment of this entity. The present case report describes an alternative minimally invasive technique/approach. This technique may reduce surgical risks of the continuity resection through an extraoral approach (nerve damage, scarring) and can improve the long-term stability of the mandible by bone preservation.

Intelligent electromagnetic navigation system for robot-assisted intraoral osteotomy in mandibular tumor resection: a model experiment.

Background: Mandibular tumor surgery necessitates precise osteotomies based on tumor boundaries; however, conventional osteotomies often lack accuracy in predicting osteotomy positions and planes, potentially leading to excessive resection of normal bone tissues or residual tumors, thus compromising postoperative quality of life and clinical outcomes. Robotic-assisted surgery (RAS) augmented with artificial intelligence (AI) offers precise localization capabilities, aiding surgeons in achieving accurate osteotomy positioning. This study aimed to evaluate the feasibility and accuracy of a robotic magnetic navigation system for positioning and osteotomy in an intraoral surgical trial of a mandibular tumor model. Methods: Patient computed tomography (CT) imaging data of mandibular chin and body tumors were utilized to create 3D printed models, serving as study subjects for mandibular tumor resection. Ten pairs of models were printed for the experimental and control groups. The experimental group (EG) underwent osteotomy using a robot-assisted surgical navigation system, performing osteotomy under robotic navigation following alignment based on preoperative design. The control group (CG) underwent traditional surgery, estimating osteotomy position empirically according to preoperative design. Postoperative CT scans were conducted on both models, and actual postoperative results were compared to preoperative design. Osteotomy accuracy was evaluated by positional and angular errors between preoperatively designed and actual osteotomy planes. Results: For ten randomly selected spots on the left and right sides, respectively, the EG group had mean distance errors of 0.338 mm and 0.941 mm. These values were obtained from the EG group. In the EG group, on the left side, the mean angular errors were 14.741 degrees, while on the right side, they were 13.021 degrees. For the 10 randomly selected spots on the left and right sides, respectively, the CG had mean distance errors of 1.776 mm and 2.320 mm. This is in contrast to the results obtained by the EG. It was determined that the left side had a mean angle error of 16.841 degrees, while the right side had an error of 18.416 degrees in the CG group. The above results indicated significantly lower point errors of bilateral osteotomy planes in the experimental group compared to the control group. Conclusion: This study demonstrates the feasibility of electromagnetic navigation robot-assisted intraoral osteotomy for mandibular tumors and suggests that this approach can enhance the precision of clinical surgery.

Unicystic ameloblastoma: Clinico-radiological and histopathological correlation with management.

Unicystic ameloblastoma is a distinct entity of ameloblastoma characterized by slow growth and locally aggressive behavior. This retrospective study aimed to assess the efficacy of different treatment modalities of unicystic ameloblastoma, focusing on clinico-radiological and histopathological features. Data from patients diagnosed with unicystic ameloblastoma were retrospectively analyzed. Patients were categorized into luminal and intraluminal (Group A) and mural (Group B) variants based on the Ackermann classification, which has a significant influence on their biological behavior, treatment approaches, and prognosis. Patients in Group A underwent enucleation with chemical cauterization, peripheral ostectomy, and iodoform packing, whereas those in Group B were treated with resection and reconstruction. Post-operatively, the patients were subjected to radiographic assessments via digital orthopantomogram at regular intervals. Because of the rarity of unicystic ameloblastoma, only 17 patients were included in the study (Group A: 9 patients; Group B: 8 patients), with a mean follow-up of 4.9 years (range: 1.4-11.8 years). The primary outcome measure was the absence of recurrence, which indicated treatment success. No patient in either group experienced recurrence within the follow-up period. This study provides evidence supporting the successful treatment of luminal and intraluminal variants of unicystic ameloblastoma in young individuals using a conservative approach. However, the more aggressive mural variant demonstrated favorable outcomes with radical treatment. These findings emphasize the importance of the Ackermann classification in guiding treatment decisions for unicystic ameloblastoma and contribute valuable insights into optimizing therapeutic strategies based on clinico-radiological and histopathological findings.

Segmental mandibulectomy and microvascular reconstruction with fibula free flap: Comparison between intraoral and extraoral approaches.

BACKGROUND: Segmental mandibulectomy and reconstruction of resulting defect can be performed via intraoral approach (IOA) or extraoral approach (EOA). Both approaches have advantages, disadvantages, indications, and contraindications to consider during their selection. OBJECTIVE: To compare IOA vs EOA of segmental mandibulectomy and microvascular reconstruction with fibula free flap (FFF). METHODS: We conducted a retrospective cohort study in which 51 patients who underwent segmental mandibulectomy and microvascular reconstruction with FFF from 2020 to 2024 were included, especially 17 patients by IOA and 34 patients by EOA, representing both groups of this study. Clinical characteristics, surgery parameters, and patients' prognosis were evaluated. Patients' satisfaction and Derriford Appearance Scale (DAS59) were assessed during follow-up. RESULTS: Ameloblastoma was the most frequent diagnosis (52.9% managed by IOA vs 70.6% by EOA); FFF was frequently positioned as double barrel (94.1% managed by IOA vs 88.2% by EOA). Compared with EOA group, IOA group had less intraoperative blood loss (mean difference [MD] = -112.2, 95% confidence interval [CI]: -178.9 to -45.5, p = 0.001), higher satisfaction score (MD = 1.3, 95% CI: 0.9 to 1.7, p ˂ 0.001), and lower DAS59 score (MD = -0.5, 95% CI: -0.7 to -0.2, p ˂ 0.001). CONCLUSION: Both IOA and EOA were found safe and feasible, presenting similar perioperative features and postoperative outcomes. Patients managed with IOA were more satisfied with aesthetic outcomes than patients managed with EOA. In the absence of simultaneous immediate implant during mandibular FFF reconstruction, after stability of FFF on the defect site, patients should always be referred to an implantologist and/or prosthodontist for teeth restoration to improve functional and aesthetic outcomes.

A three-dimensional quantitative assessment on bony growth and symmetrical recovery of mandible after decompression for unicystic ameloblastoma.

Unicystic ameloblastoma (UAM) of the jaw can be effectively reduced in volume through decompression, which promotes bone regeneration and restores jaw symmetry. This study quantitatively evaluated changes in mandible volume and symmetry following decompression of mandibular UAM. This study included 17 patients who underwent surgical decompression followed by second-stage curettage for mandibular UAM. Preoperative and postoperative three-dimensional computed tomography (CT) images were collected. Bone volume and the area of cortical perforation were measured to assess bone growth during decompression. Mandibular volumetric symmetry was analyzed by calculating the volumetric ratio of the two sides of the mandible. Twelve pairs of landmarks were identified on the surface of the lesion regions, and their coordinates were used to calculate the mean asymmetry index (AI) of the mandible. Paired t-tests and the Mann-Whitney U test were used for statistical analysis, with p < 0.05 considered indicative of statistical significance. The mean duration of decompression was 9.41 ± 3.28 months. The mean bone volume increased by 8.07 ± 2.41%, and cortical perforation recovery was 71.97 ± 14.99%. The volumetric symmetry of the mandible improved significantly (p < 0.05), and a statistically significant decrease in AI was observed (p < 0.05). In conclusion, UAM decompression enhances bone growth and symmetry recovery of the mandible. The present evaluation technique is clinically useful for quantitatively assessing mandibular asymmetry.

Ossifying fibroma: the peripheral variant.

Introduction: Peripheral ossifying fibroma (POF) is a solitary gingival growth thought to arise from the gingiva, periosteum or the periodontal ligament. It is a slow-growing, benign, progressive lesion that is limited in size. Case description: This article describes a case of ossifying fibroma of a peripheral variant that occurred in a 26-year-old female in the anterior region of the lower jaw and presented as a growth on the gingiva. Since it was difficult to diagnose clinically, a pathological evaluation was mandatory. Upon pathological confirmation of the diagnosis, the lesion was surgically excised up to the periosteum. This was deemed to be the required treatment yet, since the recurrence rate is high for POF (8% to 20%), the patient must be followed up yearly to check for recurrence.

Introduction: Le fibrome ossifiant périphérique (FOP) est une excroissance gingivale solitaire dont on pense qu'elle provient des gencives, du périoste ou du ligament parodontal. Il s'agit d'une lésion progressive, bénigne et à croissance lente dont la taille est limitée. Description du cas: Cet article décrit le cas d'une variante périphérique du fibrome ossifiant survenue chez une femme de 26 ans, dans la région antérieure de sa mâchoire inférieure et se présentant comme une excroissance sur la gencive. Comme il était difficile d'établir un diagnostic clinique, une évaluation pathologique a été nécessaire. Après confirmation pathologique du diagnostic, la lésion a été excisée jusqu'au périoste lors d'une opération chirurgicale. On a jugé ce traitement nécessaire, puisque le taux de récidive du FOP est élevé (entre 8 % et 20 %). La patiente doit faire l'objet d'un suivi annuel pour rechercher toute récidive éventuelle.

Odontome and its pathological effect on surrounding teeth.

Odontoma is the most common odontogenic tumour derived from both epithelial and mesenchymal components of the tooth-forming apparatus. It is commonly diagnosed in the second and third decades of life when a radiograph is taken for some other purpose, as most cases are asymptomatic. This case involves a young boy, with the chief complaint of pain and swelling in the lower left back region. An intraoral examination revealed a carious and hypoplastic left permanent mandibular first molar. Although the molar was suspected as the source of his symptoms, radiographic imaging revealed multiple odontomas and missing second and third molar tooth buds. This case highlights the pathological effects of odontomas on surrounding teeth, including the malformation of the first molar and aplasia of the second and third molars. The sole management depends on the early diagnosis, histopathological examination to rule out malignancy and conservative surgical excision of these tissues.

Carbon-ion radiotherapy for clear cell odontogenic carcinomas.

BACKGROUND: Clear cell odontogenic carcinoma (CCOC) is a rare odontogenic malignant tumor. The standard treatment for CCOC is surgical resection and adjuvant radiotherapy (RT). Radiotherapy is generally considered in inoperable cases. However, there are no reports on definitive RT for CCOC, and the role of RT in patients with inoperable CCOC remains unknown. Therefore, in this report, we present two cases of carbon-ion (C-ion) RT for CCOC. CASE PRESENTATION: In case 1, a 73-year-old man with mandibular CCOC presented with recurrence in the inferior temporal fossa after two tumor resections. The tumor was considered inoperable, and C-ion RT (57.6 Gy in 16 fractions) was administered. The tumor remained controlled even after 20 months of C-ion RT; however, the patient died of other causes. In case 2, a 34-year-old man with maxillary CCOC presented with recurrence in the left sinonasal region after two tumor resections. The tumor was considered inoperable, and C-ion RT (64 Gy in 16 fractions) was administered. However, recurrence was observed in the irradiated field 19 months after the treatment. Subsequently, C-ion RT (64 Gy in 16 fractions) was repeated for the recurrent tumors. Seven years and 6 months after the initial irradiation, the tumor remains controlled, and the patient is alive without any unexpected serious adverse events. CONCLUSION: C-ion RT may be an effective treatment option for patients with inoperable CCOC.

Giant cell granuloma and neurofibroma in the mandible of a patient with neurofibromatosis type 1: a long-term follow-up case report with radiological and surgical aspects and a review of the literature.

BACKGROUND: Magnetic resonance imaging (MRI) of the brain is frequently performed on patients with neurofibromatosis type 1 (NF1), to detect and follow-up intracranial findings. In addition, NF1-related pathologies can appear in the jaws. This case study investigates if it is advantageous to assess the depicted parts of the jaws in the imaging of NF1 patients with intracranial findings, thereby detecting jaw pathologies in their initial stages. CASE PRESENTATION: We report on the 3-year management with clinical and radiological follow-ups of a central giant cell granuloma and a neurofibroma in the mandible of a patient with NF1 who underwent examinations with brain MRIs. A review of the mandible in the patient's MRIs disclosed lesions with clear differences in progression rates. CONCLUSION: NF1-related jaw pathologies may be detected in the early stages if the depicted parts of the jaws are included in the assessment of the imaging of NF1 patients with intracranial findings. This could impact the treatment of eventual pathologies before lesion progression and further damage to the vicinity.

[Komplexes Odontom im Unterkieferfrontzahnbereich bei einer 16-jährigen Patientin - Diagnostik, Therapie und Nachsorge].

Odontome gelten zusammen mit den Amelo- blastomen als die häufigsten odontogenen Tumoren. Sie entstehen während der embryo- nalen Zahnkeimentwicklung durch fehlerhaft differenziertes Keimgewebe und werden daher auch als Hamartome bezeichnet. Somit sind sie also strenggenommen keine klassischen Neoplasien.

Does Free Fibular Flap Reconstruction Affect the Quality of Life in Pediatric Patients With Various Extend of Mandible Defects?

BACKGROUND: The long-term outcomes in pediatric patients with various extents of mandible defects have not been well-documented. METHODS: A retrospective case series in which this study looked at pediatric patients under the age of 13 who had mandibular reconstruction with free fibular flap and had not received another operation in the previous 6 months. The eating, swallowing, speech function, and quality of life are evaluated with EORTC QLQ-H&N35 after the mandible growth spurt has occurred. RESULTS: A total of 7 patients were included in this study with operation ages ranging from 6 years 1 month to 12 years 2 months. The etiology of malignant tumors was found in 2 patients and benign tumors in 5 patients. The mandibular defect distribution consists of 1 class Ic, 1 class II, 2 class IIc, 2 class III, and 1 class IVc. All patients reported no swallowing or speech difficulties. However, transient eating trouble was seen in 1 patient due to the extensive defect size that causes tooth loss. Only 1 patient received dental rehabilitation. The patients displayed an overall good quality of life with an average score of 2.857. CONCLUSIONS: Free fibular flap for mandibular reconstruction in children who have not reached their mandibular growth peak have a satisfying outcome, both in their function and quality of life.

Aggressive Late Recurrence of a Calcifying Epithelial Odontogenic Tumor: Surgical Refinements Based on New Technologies.

A calcifying epithelial odontogenic tumor is a rare, benign odontogenic neoplasm. Surgical treatment is the option, and late recurrence is very rare. Radiologically, the lesions are commonly present scattered calcifications. This case report details a 64-year-old female patient with a recurrence of a right mandibular calcifying epithelial odontogenic tumor 2 decades after successful initial surgical removal. A segmental mandibulectomy and immediate reconstruction were performed using a planned vascularized free fibula flap with virtual surgery, custom reconstruction plate, and intraoperative computed tomography. Modifications were made to the design of the reconstruction plate to improve the cervicofacial profile and subsequent rehabilitation with dental implants. Fully guided implant surgery with point-of-care manufacturing protocol was done to improve prosthetically driven implant planning. The case presented highlights the usefulness of new technologies for mandibular reconstruction with the free fibula flap and the concept of point-of-care with technical notes that increase precision and reduce morbidity in implant-supported rehabilitation.

Odontogenic carcinoma with dentinoid: case report and literature review of a rare entity.

BACKGROUND: Odontogenic carcinoma with dentinoid (OCD) is a rare and controversial entity, which has not yet been included in the current World Health Organization classification of odontogenic lesions. Owing to the small number of reported cases, the clinicopathological characteristics, biological behavior, prognosis, and appropriate treatment strategies for OCD remain to be defined. Herein, we present an additional case of OCD with a focus on the differential diagnosis and review of the pertinent literature, in order to enable better recognition by oral clinicians and pathologists and further characterization of this entity. CASE PRESENTATION: This paper reports a case of OCD in the posterior mandible of a 22-year-old female. Radiography showed a well-defined unilocular radiolucency with radiopaque materials. The intraoperative frozen section pathology gave a non-committed diagnosis of odontogenic neoplasm with uncertain malignant potential. Then a partial mandibulectomy with free iliac crest bone graft and titanium implants was performed. Microscopically, the tumor consisted of sheets, islands, and cords of round to polygonal epithelial cells associated with an abundant dentinoid matrix. Immunohistochemically, the tumor cells were diffusely positive for CK19, p63, and ß-catenin (cytoplasmic and nuclear). No rearrangement of the EWSR1 gene was detected. The final diagnosis was OCD. There has been no evidence of recurrence or metastasis for 58 months after surgery. We also provide a literature review of OCD cases, including one case previously reported as ghost cell odontogenic carcinoma from our hospital. CONCLUSIONS: OCD is a locally aggressive low grade malignancy without apparent metastatic potential. Wide surgical excision with clear margins and long-term period follow-up to identify any possible recurrence or metastases are recommended. Histopathological examination is essential to conclude the diagnosis. Special care must be taken to distinguish OCD from ghost cell odontogenic carcinoma and clear cell odontogenic carcinoma, as misdiagnosis might lead to unnecessary overtreatment. Study of additional cases is required to further characterize the clinicopathological features and clarify the nosologic status and biological behavior of this tumor.

Alberta reconstructive technique (ART): An innovative approach using digital surgical design and simulation in advanced jaw reconstruction with occlusion-based prefabricated vascularized fibular flaps and primary osseointegrated implant installation.

The Alberta reconstructive technique (ART) is an innovative surgical procedure performed on patients undergoing primary jaw resection and reconstruction. The ART procedure was developed in collaboration with the Institute for Reconstructive Sciences in Medicine and the Division of Otolaryngology-Head and Neck Surgery, University of Alberta.

[Application of mixed reality technology in free fibular flap transplantation for repairing mandibular defects].

Objective: To explore the feasibility and effectiveness of mixed reality technology for localizing perforator vessels in the repair of mandibular defects using free fibular flap. Methods: Between June 2020 and June 2023, 12 patients with mandibular defects were repaired with free fibular flap. There were 8 males and 4 females, with an average age of 61 years (range, 35-78 years). There were 9 cases of ameloblastomas and 3 cases of squamous cell carcinomas involving the mandible. The disease duration ranged from 15 days to 2 years (median, 14.2 months). The length of mandibular defects ranged from 5 to 14 cm (mean, 8.5 cm). The area of soft tissue defects ranged from 5 cm×4 cm to 8 cm×6 cm. Preoperative enhanced CT scans of the maxillofacial region and CT angiography of the lower limbs were performed, and the data was used to create three-dimensional models of the mandible and lower limb perforator vessels. During operation, the mixed reality technology was used to overlay the three-dimensional model of perforator vessels onto the body surface for harvesting the free fibular flap. The length of the fibula harvested ranged from 6 to 15 cm, with a mean of 9.5 cm; the size of the flap ranged from 6 cm×5 cm to 10 cm×8 cm. The donor sites were sutured directly in 7 cases and repaired with free skin grafting in 5 cases. Results: Thirty perforator vessels were located by mixed reality technology before operation, with an average of 2.5 vessels per case; the distance between the exit point of the perforator vessels located before operation and the actual exit point ranged from 1 to 4 mm, with a mean of 2.8 mm. All fibular flaps survived; 1 case had necrosis at the distal end of flap, which healed after dressing changes. One donor site had infection, which healed after anti-inflammatory dressing changes; the remaining incisions healed by first intention, and the grafts survived smoothly. All patients were followed up 8-36 months (median, 21 months). The repaired facial appearance was satisfactory, with no flap swelling. Among the patients underwent postoperative radiotherapy, 2 patients had normal bone healing and 1 had delayed healing at 6 months. Conclusion: In free fibular flap reconstruction of mandibular defects, the use of mixed reality technology for perforator vessel localization can achieve three-dimensional visualization, simplify surgical procedures, and reduce errors.

Recurrent cementoblastoma with multifocal growth and cellular atypia: a case report.

BACKGROUND: Cementoblastoma is a rare odontogenic tumor characterized by the formation of osteocementum-like tissue on a tooth root directly by neoplastic cementoblasts. Although it is categorized as benign, it has a high potential for growth with a certain degree of recurrence risk. However, there are only a few studies describing the features of recurrent cementoblastoma. The diagnosis of recurrent cementoblastoma is challenging not only due to its cytological atypia but also because of its large size and multicentric growth pattern. These characteristics suggest a potential for malignancy. CASE PRESENTATION: A 29-year-old woman was transferred to our university dental hospital complaining of swelling of the right mandible. She had a history of enucleation of cementoblastoma associated with the third molar of the right mandible. Five years after the initial treatment, imaging demonstrated well-circumscribed multicentric radiopaque lesions in the same area. Histologically, the lesion consisted of osteocementum-like tissue rimmed with polygonal or plump tumor cells. Several cells were large epithelioid cells with bizarre nucleoli, which may be reminiscent of malignant tumors. Otherwise, there were no apparent malignant findings, including proliferative activity or atypical mitotic figure. Besides, tumor cells were positive for c-FOS, a marker of osteoblastoma and cementoblastoma. Eventually, the patient was diagnosed with recurrent cementoblastoma. CONCLUSIONS: Pathological analyses of this case suggested that the recurrent event in the cementoblastoma altered its growth pattern and tumor cell shape. Moreover, in the case of enucleation surgery, long-term follow-up is important because there is some recurrent risk of cementoblastoma, although it is not high.